Abstract. The generic hoist scheduling problem is NP-hard and arises from automated manufacturing... more Abstract. The generic hoist scheduling problem is NP-hard and arises from automated manufacturing lines. In recent work using the constraint logic programming (CLP) formalism, a unified model has been developed with the problem description and solution method separated. We provide an improved model and new preprocessing stages where, as before, solutions and proof of optimality are provided by a hybrid CLP-MIP algorithm. The new algorithm is more scalable and robust. We give empirical results for a range of problem classes on benchmark problems from several sources.
--- Version en Espanol Esta contribucion presenta la experiencia del Master Universitario en Inge... more --- Version en Espanol Esta contribucion presenta la experiencia del Master Universitario en Ingenieria Informatica de la Universitat Oberta de Catalunya (UOC). Este Master es un titulo oficial de 78 ECTS adaptado a las recomendaciones del Consejo de Universidades para el diseno de titulos de Master en Ingenieria Informatica. Fue verificado favorablemente por ANECA y fue el primer Master del estado espanol en obtener el sello internacional de calidad Euro-Inf otorgado por EQANIE. El Master se imparte desde el curso 2011-2012 en modalidad no presencial a traves de un Campus Virtual, con unos 200 estudiantes en activo. El objetivo de esta contribucion es profundizar en los retos y particularidades de la docencia online en un titulo de Master en Ingenieria Informatica. Destacamos especialmente el impacto que tiene en el diseno y desarrollo del Master el perfil tipo de estudiante (con dedicacion a tiempo parcial por compaginar el estudio con su actividad profesional y responsabilidades personales). Clasificacion: K.3 Ordenadores y educacion Palabras clave: K.3.1 [Aplicaciones de ordenadores en educacion]: Ensenanza a distancia K.3.2 [Educacion en informatica]: Ingenieria Informatica, Curriculum---Master, EEES ---- Version en Ingles This paper presents the experience of the Masters programme in Computing Engineering at the Open University of Catalonia (UOC). This Master is an official degree of 78 ECTS which adheres to the recommendations of the Spanish Consejo de Universidades about the design of Master degrees in Computing Engineering. It was officially approved by ANECA (the Spanish University Quality Assurance organization) and it was the first Masters in Spain to achieve the Euro-Inf international quality seal awarded by EQANIE. This Master is offered since the academic year 2011-2012 using distance learning through a Virtual Campus, with about 200 students currently enrolled. The goal of this paper is to study the challenges and specificities of online education in a Masters programme in Computing Engineering. In particular, we highlight the impact of the typical student profile (studying part-time as he combines study with a professional activity or family responsibilities) in the design and development of the programme. Subject area: K.3 Computers and Education Keywords: K.3.1 [Computer Uses in Education]: Distance Learning K.3.2 [Computer and Information Science Education]: Computer science education, Curriculum---masters level, EHEA
Vehicle Routing Problems (VRPs) cover a wide range of well-known NP-hard problems where the aim i... more Vehicle Routing Problems (VRPs) cover a wide range of well-known NP-hard problems where the aim is to serve a set of customers with a fleet of vehicles under certain constraints. Literature contains several approaches -coming from different fields like Operations Research, Artificial Intelligence and Computer Science- which try to get good (near-optimal) solutions for small-, mid- and large-size instances. The Vehicle Routing Problem with Stochastic Demands (CVRPSD) is a particular case of VRP where demands made by clients are random, which introduces uncertainty in the problem. Thus, a good aprioristic solution may become unfeasible during the delivery phase if total demand in a route exceeds total vehicle capacity. This paper presents a flexible approach for the CVRPSD, which is based on the combined use of Monte Carlo simulation and reliability indices. Our methodology provides a set of alternative solutions for a given CVRPSD instance. These solutions depend on a parameter which...
L�evolucio del World Wide Web (o simplement web) des del seu naixement a la decada dels vuitanta ... more L�evolucio del World Wide Web (o simplement web) des del seu naixement a la decada dels vuitanta del segle xx ha estat gegant. La incorporacio de nous usuaris, exponencial en el temps, aixi com l�aportacio constant de noves maneres d�organitzar les dades, comunicar-se, compartir informacio, etc., han fet que el web hagi assolit en nomes dues decades una inercia practicament imparable. El novembre de 2006 es crea la Web Science Research Initiative (WSRI) amb l�objectiu principal de proposar una nova disciplina, la «ciencia del web» (Web Science), que observi la xarxa i tot allo que l�envolta. Defensa la necessitat d�analitzar que passa dins i fora de la xarxa i, d�aquesta manera, poder-hi proposar millores o correccions. Aquesta idea implica combinar disciplines tan llunyanes fins ara com la informatica, la psicologia, el dret o l�economia. Tot aixo implica l�aparicio d�un nou perfil professional, el cientific del web, i, per tant, de noves necessitats academiques. Aquest article mos...
Simheuristics combine metaheuristics with simulation in order to solve the optimization problems ... more Simheuristics combine metaheuristics with simulation in order to solve the optimization problems with stochastic elements. This paper introduces the concept of fuzzy simheuristics, which extends the simheuristics approach by making use of fuzzy techniques, thus allowing us to tackle optimization problems under a more general scenario, which includes uncertainty elements of both stochastic and non-stochastic nature. After reviewing the related work, the paper discusses, in detail, how the optimization, simulation, and fuzzy components can be efficiently integrated. In order to illustrate the potential of fuzzy simheuristics, we consider the team orienteering problem (TOP) under an uncertainty scenario, and perform a series of computational experiments. The obtained results show that our proposed approach is not only able to generate competitive solutions for the deterministic version of the TOP, but, more importantly, it can effectively solve more realistic TOP versions, including st...
The Capacitated Arc Routing Problem (CARP) is a combinatorial optimization problem similar to the... more The Capacitated Arc Routing Problem (CARP) is a combinatorial optimization problem similar to the well-known Capacitated Vehicle Routing Problem (CVRP). In the CARP, the customers' demands are located on the edges (arcs) of a general (not necessarily complete) graph. This is in contrast to the CVRP, where demand is located on the nodes of a complete graph. While the CVRP has been extensively studied over the past couple of decades, the number of articles and research results on the CARP is significantly lower. To partially fill ...
This paper presents a first approach to a constraint programming-based library for the modelling ... more This paper presents a first approach to a constraint programming-based library for the modelling of general vehicle routing problems (VRP). In this work we present a set of constraints and cost functions written in ECLiPSe, a well known Constraint Programming (CP) language, which can be combined to build different VRP models without rewriting.
Abstract. Since their introduction, local search algorithms and in particular tabu search algor... more Abstract. Since their introduction, local search algorithms and in particular tabu search algorithms have consistently represented the state-of-the-art in so-lution techniques for the classical job-shop scheduling problem. This is despite the availability of powerful search and ...
This paper presents a first approach to a constraint programming-based library for the modelling ... more This paper presents a first approach to a constraint programming-based library for the modelling of general vehicle routing problems (VRP). In this work we present a set of constraints and cost functions written in ECLiPSe, a well known Constraint Programming (CP) language, which can be combined to build different VRP models without rewriting.
Proceedings of 5th the International Conference on Operations Research and Enterprise Systems, 2016
In this paper a flexible hybrid methodology, combining Ant Colony Optimisation (ACO) and Constrai... more In this paper a flexible hybrid methodology, combining Ant Colony Optimisation (ACO) and Constraint Programming (CP), is presented for solving Vehicle Routing Problems (VRP). The stress of this methodology is on the word 'flexible': It gives reasonably good results to changing problems without high solution redesign efforts. Thus a different problem with a new set of constraints and objectives requires no changes to the search algorithm. The search part (driven by ACO) and the model of the problem (included in the CP part) are separated to take advantage of their best attributes. This separation makes the application of the framework to different problems much simpler. To assess the feasibility of our approach, we have used it to solve different instances of the VRP family. These instances are built by combining different sets of constraints. The results obtained are promising but show that the methodology needs deeper communication between ACO and CP to improve its performance.
Degree curriculums reaction to changes in society is extremely slow. This becomes ever clearer wh... more Degree curriculums reaction to changes in society is extremely slow. This becomes ever clearer when talking about technology-based disciplines like those proposed in the ACM computer curricula. This paper defends that computer-related curriculums have already lived three different stages-regarding the appearance and proliferation of digital communications and the Web. Furthermore, it seems these curriculums have become already exhausted and are facing the need of a new one. This change comes directly linked to the evolution of the Web towards the Web 2.0 and the every time deeper participation of users on it. New ways of communication, new relationships between users on the Web require new education to those involved on it. Old curriculums are not able to deal with all these new issues. A renovation is necessary. May "Web Science" be the solution?
2015 7th International Conference on Games and Virtual Worlds for Serious Applications (VS-Games), 2015
This paper presents a review of the literature on gamification design frameworks. Gamification, u... more This paper presents a review of the literature on gamification design frameworks. Gamification, understood as the use of game design elements in other contexts for the purpose of engagement, has become a hot topic in the recent years. However, there’s also a cautionary tale to be extracted from Gartner’s reports on the topic: many gamification-based solutions fail because, mostly, they have been created on a whim, or mixing bits and pieces from game components, without a clear and formal design process. The application of a definite design framework aims to be a path to success. Therefore, before starting the gamification of a process, it is very important to know which frameworks or methods exist and their main characteristics. The present review synthesizes the process of gamification design for a successful engagement experience. This review categorizes existing approaches and provides an assessment of their main features, which may prove invaluable to developers of gamified solutions at different levels and scopes.
The Vehicle Routing Problem with Time Windows is a NP-hard routing problem where the demand is lo... more The Vehicle Routing Problem with Time Windows is a NP-hard routing problem where the demand is located in nodes and should be completely served fulfilling certain scheduling constraints for delivering. This paper presents a randomized algorithm which combines a classical heuristic with biased random sampling in order to solve this type of problem. This new algorithm is compared with one version of the Insertion heuristic of Solomon, reaching results which outperform it. As discussed in the paper, the methodology presented is flexible, can be easily parallelized and it does not require any complex finetuning process. Some preliminary tests show the potential of the proposed approach as well as its limitations.
This paper presents a first approach to a constraint programming-based library for the modelling ... more This paper presents a first approach to a constraint programming-based library for the modelling of general vehicle routing problems (VRP). In this work we present a set of constraints and cost functions written in ECLiPSe, a well known Constraint Programming (CP) language, which can be combined to build different VRP models without rewriting.
Abstract. The generic hoist scheduling problem is NP-hard and arises from automated manufacturing... more Abstract. The generic hoist scheduling problem is NP-hard and arises from automated manufacturing lines. In recent work using the constraint logic programming (CLP) formalism, a unified model has been developed with the problem description and solution method separated. We provide an improved model and new preprocessing stages where, as before, solutions and proof of optimality are provided by a hybrid CLP-MIP algorithm. The new algorithm is more scalable and robust. We give empirical results for a range of problem classes on benchmark problems from several sources.
--- Version en Espanol Esta contribucion presenta la experiencia del Master Universitario en Inge... more --- Version en Espanol Esta contribucion presenta la experiencia del Master Universitario en Ingenieria Informatica de la Universitat Oberta de Catalunya (UOC). Este Master es un titulo oficial de 78 ECTS adaptado a las recomendaciones del Consejo de Universidades para el diseno de titulos de Master en Ingenieria Informatica. Fue verificado favorablemente por ANECA y fue el primer Master del estado espanol en obtener el sello internacional de calidad Euro-Inf otorgado por EQANIE. El Master se imparte desde el curso 2011-2012 en modalidad no presencial a traves de un Campus Virtual, con unos 200 estudiantes en activo. El objetivo de esta contribucion es profundizar en los retos y particularidades de la docencia online en un titulo de Master en Ingenieria Informatica. Destacamos especialmente el impacto que tiene en el diseno y desarrollo del Master el perfil tipo de estudiante (con dedicacion a tiempo parcial por compaginar el estudio con su actividad profesional y responsabilidades personales). Clasificacion: K.3 Ordenadores y educacion Palabras clave: K.3.1 [Aplicaciones de ordenadores en educacion]: Ensenanza a distancia K.3.2 [Educacion en informatica]: Ingenieria Informatica, Curriculum---Master, EEES ---- Version en Ingles This paper presents the experience of the Masters programme in Computing Engineering at the Open University of Catalonia (UOC). This Master is an official degree of 78 ECTS which adheres to the recommendations of the Spanish Consejo de Universidades about the design of Master degrees in Computing Engineering. It was officially approved by ANECA (the Spanish University Quality Assurance organization) and it was the first Masters in Spain to achieve the Euro-Inf international quality seal awarded by EQANIE. This Master is offered since the academic year 2011-2012 using distance learning through a Virtual Campus, with about 200 students currently enrolled. The goal of this paper is to study the challenges and specificities of online education in a Masters programme in Computing Engineering. In particular, we highlight the impact of the typical student profile (studying part-time as he combines study with a professional activity or family responsibilities) in the design and development of the programme. Subject area: K.3 Computers and Education Keywords: K.3.1 [Computer Uses in Education]: Distance Learning K.3.2 [Computer and Information Science Education]: Computer science education, Curriculum---masters level, EHEA
Vehicle Routing Problems (VRPs) cover a wide range of well-known NP-hard problems where the aim i... more Vehicle Routing Problems (VRPs) cover a wide range of well-known NP-hard problems where the aim is to serve a set of customers with a fleet of vehicles under certain constraints. Literature contains several approaches -coming from different fields like Operations Research, Artificial Intelligence and Computer Science- which try to get good (near-optimal) solutions for small-, mid- and large-size instances. The Vehicle Routing Problem with Stochastic Demands (CVRPSD) is a particular case of VRP where demands made by clients are random, which introduces uncertainty in the problem. Thus, a good aprioristic solution may become unfeasible during the delivery phase if total demand in a route exceeds total vehicle capacity. This paper presents a flexible approach for the CVRPSD, which is based on the combined use of Monte Carlo simulation and reliability indices. Our methodology provides a set of alternative solutions for a given CVRPSD instance. These solutions depend on a parameter which...
L�evolucio del World Wide Web (o simplement web) des del seu naixement a la decada dels vuitanta ... more L�evolucio del World Wide Web (o simplement web) des del seu naixement a la decada dels vuitanta del segle xx ha estat gegant. La incorporacio de nous usuaris, exponencial en el temps, aixi com l�aportacio constant de noves maneres d�organitzar les dades, comunicar-se, compartir informacio, etc., han fet que el web hagi assolit en nomes dues decades una inercia practicament imparable. El novembre de 2006 es crea la Web Science Research Initiative (WSRI) amb l�objectiu principal de proposar una nova disciplina, la «ciencia del web» (Web Science), que observi la xarxa i tot allo que l�envolta. Defensa la necessitat d�analitzar que passa dins i fora de la xarxa i, d�aquesta manera, poder-hi proposar millores o correccions. Aquesta idea implica combinar disciplines tan llunyanes fins ara com la informatica, la psicologia, el dret o l�economia. Tot aixo implica l�aparicio d�un nou perfil professional, el cientific del web, i, per tant, de noves necessitats academiques. Aquest article mos...
Simheuristics combine metaheuristics with simulation in order to solve the optimization problems ... more Simheuristics combine metaheuristics with simulation in order to solve the optimization problems with stochastic elements. This paper introduces the concept of fuzzy simheuristics, which extends the simheuristics approach by making use of fuzzy techniques, thus allowing us to tackle optimization problems under a more general scenario, which includes uncertainty elements of both stochastic and non-stochastic nature. After reviewing the related work, the paper discusses, in detail, how the optimization, simulation, and fuzzy components can be efficiently integrated. In order to illustrate the potential of fuzzy simheuristics, we consider the team orienteering problem (TOP) under an uncertainty scenario, and perform a series of computational experiments. The obtained results show that our proposed approach is not only able to generate competitive solutions for the deterministic version of the TOP, but, more importantly, it can effectively solve more realistic TOP versions, including st...
The Capacitated Arc Routing Problem (CARP) is a combinatorial optimization problem similar to the... more The Capacitated Arc Routing Problem (CARP) is a combinatorial optimization problem similar to the well-known Capacitated Vehicle Routing Problem (CVRP). In the CARP, the customers' demands are located on the edges (arcs) of a general (not necessarily complete) graph. This is in contrast to the CVRP, where demand is located on the nodes of a complete graph. While the CVRP has been extensively studied over the past couple of decades, the number of articles and research results on the CARP is significantly lower. To partially fill ...
This paper presents a first approach to a constraint programming-based library for the modelling ... more This paper presents a first approach to a constraint programming-based library for the modelling of general vehicle routing problems (VRP). In this work we present a set of constraints and cost functions written in ECLiPSe, a well known Constraint Programming (CP) language, which can be combined to build different VRP models without rewriting.
Abstract. Since their introduction, local search algorithms and in particular tabu search algor... more Abstract. Since their introduction, local search algorithms and in particular tabu search algorithms have consistently represented the state-of-the-art in so-lution techniques for the classical job-shop scheduling problem. This is despite the availability of powerful search and ...
This paper presents a first approach to a constraint programming-based library for the modelling ... more This paper presents a first approach to a constraint programming-based library for the modelling of general vehicle routing problems (VRP). In this work we present a set of constraints and cost functions written in ECLiPSe, a well known Constraint Programming (CP) language, which can be combined to build different VRP models without rewriting.
Proceedings of 5th the International Conference on Operations Research and Enterprise Systems, 2016
In this paper a flexible hybrid methodology, combining Ant Colony Optimisation (ACO) and Constrai... more In this paper a flexible hybrid methodology, combining Ant Colony Optimisation (ACO) and Constraint Programming (CP), is presented for solving Vehicle Routing Problems (VRP). The stress of this methodology is on the word 'flexible': It gives reasonably good results to changing problems without high solution redesign efforts. Thus a different problem with a new set of constraints and objectives requires no changes to the search algorithm. The search part (driven by ACO) and the model of the problem (included in the CP part) are separated to take advantage of their best attributes. This separation makes the application of the framework to different problems much simpler. To assess the feasibility of our approach, we have used it to solve different instances of the VRP family. These instances are built by combining different sets of constraints. The results obtained are promising but show that the methodology needs deeper communication between ACO and CP to improve its performance.
Degree curriculums reaction to changes in society is extremely slow. This becomes ever clearer wh... more Degree curriculums reaction to changes in society is extremely slow. This becomes ever clearer when talking about technology-based disciplines like those proposed in the ACM computer curricula. This paper defends that computer-related curriculums have already lived three different stages-regarding the appearance and proliferation of digital communications and the Web. Furthermore, it seems these curriculums have become already exhausted and are facing the need of a new one. This change comes directly linked to the evolution of the Web towards the Web 2.0 and the every time deeper participation of users on it. New ways of communication, new relationships between users on the Web require new education to those involved on it. Old curriculums are not able to deal with all these new issues. A renovation is necessary. May "Web Science" be the solution?
2015 7th International Conference on Games and Virtual Worlds for Serious Applications (VS-Games), 2015
This paper presents a review of the literature on gamification design frameworks. Gamification, u... more This paper presents a review of the literature on gamification design frameworks. Gamification, understood as the use of game design elements in other contexts for the purpose of engagement, has become a hot topic in the recent years. However, there’s also a cautionary tale to be extracted from Gartner’s reports on the topic: many gamification-based solutions fail because, mostly, they have been created on a whim, or mixing bits and pieces from game components, without a clear and formal design process. The application of a definite design framework aims to be a path to success. Therefore, before starting the gamification of a process, it is very important to know which frameworks or methods exist and their main characteristics. The present review synthesizes the process of gamification design for a successful engagement experience. This review categorizes existing approaches and provides an assessment of their main features, which may prove invaluable to developers of gamified solutions at different levels and scopes.
The Vehicle Routing Problem with Time Windows is a NP-hard routing problem where the demand is lo... more The Vehicle Routing Problem with Time Windows is a NP-hard routing problem where the demand is located in nodes and should be completely served fulfilling certain scheduling constraints for delivering. This paper presents a randomized algorithm which combines a classical heuristic with biased random sampling in order to solve this type of problem. This new algorithm is compared with one version of the Insertion heuristic of Solomon, reaching results which outperform it. As discussed in the paper, the methodology presented is flexible, can be easily parallelized and it does not require any complex finetuning process. Some preliminary tests show the potential of the proposed approach as well as its limitations.
This paper presents a first approach to a constraint programming-based library for the modelling ... more This paper presents a first approach to a constraint programming-based library for the modelling of general vehicle routing problems (VRP). In this work we present a set of constraints and cost functions written in ECLiPSe, a well known Constraint Programming (CP) language, which can be combined to build different VRP models without rewriting.
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